(a) General rule
Section 421(a) shall apply with respect to the transfer of a share of stock to an individual pursuant to his exercise of an option granted under an employee stock purchase plan (as defined in subsection (b)) if—

(1) no disposition of such share is made by him within 2 years after the date of the granting of the option nor within 1 year after the transfer of such share to him; and

(2) at all times during the period beginning with the date of the granting of the option and ending on the day 3 months before the date of such exercise, he is an employee of the corporation granting such option, a parent or subsidiary corporation of such corporation, or a corporation or a parent or subsidiary corporation of such corporation issuing or assuming a stock option in a transaction to which section 424(a) applies.

(b) Employee stock purchase plan
For purposes of this part, the term "employee stock purchase plan" means a plan which meets the following requirements:

(1) the plan provides that options are to be granted only to employees of the employer corporation or of its parent or subsidiary corporation to purchase stock in any such corporation;

(2) such plan is approved by the stockholders of the granting corporation within 12 months before or after the date such plan is adopted;

(3) under the terms of the plan, no employee can be granted an option if such employee, immediately after the option is granted, owns stock possessing 5 percent or more of the total combined voting power or value of all classes of stock of the employer corporation or of its parent or subsidiary corporation. For purposes of this paragraph, the rules of section 424(d) shall apply in determining the stock ownership of an individual, and stock which the employee may purchase under outstanding options shall be treated as stock owned by the employee;

(4) under the terms of the plan, options are to be granted to all employees of any corporation whose employees are granted any of such options by reason of their employment by such corporation, except that there may be excluded—

(A) employees who have been employed less than 2 years,

(B) employees whose customary employment is 20 hours or less per week,

(C) employees whose customary employment is for not more than 5 months in any calendar year, and

(D) highly compensated employees (within the meaning of section 414(q));

(5) under the terms of the plan, all employees granted such options shall have the same rights and privileges, except that the amount of stock which may be purchased by any employee under such option may bear a uniform relationship to the total compensation, or the basic or regular rate of compensation, of employees, the plan may provide that no employee may purchase more than a maximum amount of stock fixed under the plan, and the rules of section 83(i) shall apply in determining which employees have a right to make an election under such section;

(6) under the terms of the plan, the option price is not less than the lesser of—

(A) an amount equal to 85 percent of the fair market value of the stock at the time such option is granted, or

(B) an amount which under the terms of the option may not be less than 85 percent of the fair market value of the stock at the time such option is exercised;

(7) under the terms of the plan, such option cannot be exercised after the expiration of—

(A) 5 years from the date such option is granted if, under the terms of such plan, the option price is to be not less than 85 percent of the fair market value of such stock at the time of the exercise of the option, or

(B) 27 months from the date such option is granted, if the option price is not determinable in the manner described in subparagraph (A);

(8) under the terms of the plan, no employee may be granted an option which permits his rights to purchase stock under all such plans of his employer corporation and its parent and subsidiary corporations to accrue at a rate which exceeds $25,000 of fair market value of such stock (determined at the time such option is granted) for each calendar year in which such option is outstanding at any time. For purposes of this paragraph—

(A) the right to purchase stock under an option accrues when the option (or any portion thereof) first becomes exercisable during the calendar year;

(B) the right to purchase stock under an option accrues at the rate provided in the option, but in no case may such rate exceed $25,000 of fair market value of such stock (determined at the time such option is granted) for any one calendar year; and

(C) a right to purchase stock which has accrued under one option granted pursuant to the plan may not be carried over to any other option; and

(9) under the terms of the plan, such option is not transferable by such individual otherwise than by will or the laws of descent and distribution, and is exercisable, during his lifetime, only by him.

For purposes of paragraphs (3) to (9), inclusive, where additional terms are contained in an offering made under a plan, such additional terms shall, with respect to options exercised under such offering, be treated as a part of the terms of such plan.

(c) Special rule where option price is between 85 percent and 100 percent of value of stock
If the option price of a share of stock acquired by an individual pursuant to a transfer to which subsection (a) applies was less than 100 percent of the fair market value of such share at the time such option was granted, then, in the event of any disposition of such share by him which meets the holding period requirements of subsection (a), or in the event of his death (whenever occurring) while owning such share, there shall be included as compensation (and not as gain upon the sale or exchange of a capital asset) in his gross income, for the taxable year in which falls the date of such disposition or for the taxable year closing with his death, whichever applies, an amount equal to the lesser of—

(1) the excess of the fair market value of the share at the time of such disposition or death over the amount paid for the share under the option, or

(2) the excess of the fair market value of the share at the time the option was granted over the option price.

If the option price is not fixed or determinable at the time the option is granted, then for purposes of this subsection, the option price shall be determined as if the option were exercised at such time. In the case of the disposition of such share by the individual, the basis of the share in his hands at the time of such disposition shall be increased by an amount equal to the amount so includible in his gross income. No amount shall be required to be deducted and withheld under chapter 24 with respect to any amount treated as compensation under this subsection.

(d) Coordination with qualified equity grants
An option for which an election is made under section 83(i) with respect to the stock received in connection with its exercise shall not be considered as granted pursuant an employee stock purchase plan.